pc: use new CPU hotplug interface since 2.7 machine type

For compatibility reasons PC/Q35 will start with legacy
CPU hotplug interface by default but with new CPU hotplug
AML code since 2.7 machine type. That way legacy firmware
that doesn't use QEMU generated ACPI tables will be
able to continue using legacy CPU hotplug interface.

While new machine type, with firmware supporting QEMU
provided ACPI tables, will generate new CPU hotplug AML,
which will switch to new CPU hotplug interface when
guest OS executes its _INI method on ACPI tables
loading.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c
index 401ac0dab241af2e788ad260b6479ae2d2f2e240..c13b65c2c911d2b38dd691911855573ac2adb9e6 100644 (file)
--- a/hw/acpi/cpu.c
+++ b/hw/acpi/cpu.c
@@ -373,6 +373,15 @@ void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,
         aml_append(field, aml_named_field(CPU_DATA, 32));
         aml_append(cpu_ctrl_dev, field);
 
+        if (opts.has_legacy_cphp) {
+            method = aml_method("_INI", 0, AML_SERIALIZED);
+            /* switch off legacy CPU hotplug HW and use new one,
+             * on reboot system is in new mode and writing 0
+             * in CPU_SELECTOR selects BSP, which is NOP at
+             * the time _INI is called */
+            aml_append(method, aml_store(zero, aml_name(CPU_SELECTOR)));
+            aml_append(cpu_ctrl_dev, method);
+        }
     }
     aml_append(sb_scope, cpu_ctrl_dev);
 

diff --git a/hw/acpi/cpu_hotplug.c b/hw/acpi/cpu_hotplug.c
index fe75bd9ac9ee8ac460ae68940bacd9db664cb9c3..e19d902063769125d0b6ce2285feff42a809c6af 100644 (file)
--- a/hw/acpi/cpu_hotplug.c
+++ b/hw/acpi/cpu_hotplug.c
@@ -34,7 +34,15 @@ static uint64_t cpu_status_read(void *opaque, hwaddr addr, unsigned int size)
 static void cpu_status_write(void *opaque, hwaddr addr, uint64_t data,
                              unsigned int size)
 {
-    /* TODO: implement VCPU removal on guest signal that CPU can be removed */
+    /* firmware never used to write in CPU present bitmap so use
+       this fact as means to switch QEMU into modern CPU hotplug
+       mode by writing 0 at the beginning of legacy CPU bitmap
+     */
+    if (addr == 0 && data == 0) {
+        AcpiCpuHotplug *cpus = opaque;
+        object_property_set_bool(cpus->device, false, "cpu-hotplug-legacy",
+                                 &error_abort);
+    }
 }
 
 static const MemoryRegionOps AcpiCpuHotplug_ops = {
@@ -83,6 +91,17 @@ void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
     memory_region_init_io(&gpe_cpu->io, owner, &AcpiCpuHotplug_ops,
                           gpe_cpu, "acpi-cpu-hotplug", ACPI_GPE_PROC_LEN);
     memory_region_add_subregion(parent, base, &gpe_cpu->io);
+    gpe_cpu->device = owner;
+}
+
+void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
+                                CPUHotplugState *cpuhp_state,
+                                uint16_t io_port)
+{
+    MemoryRegion *parent = pci_address_space_io(PCI_DEVICE(gpe_cpu->device));
+
+    memory_region_del_subregion(parent, &gpe_cpu->io);
+    cpu_hotplug_hw_init(parent, gpe_cpu->device, cpuhp_state, io_port);
 }
 
 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index d12cc62381376ce3bf690e0102cf7e2ca8199757..e5a3c18e52d73a001c18393a7fed6651f5e4fc40 100644 (file)
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -189,6 +189,33 @@ static const VMStateDescription vmstate_tco_io_state = {
     }
 };
 
+static bool vmstate_test_use_cpuhp(void *opaque)
+{
+    ICH9LPCPMRegs *s = opaque;
+    return !s->cpu_hotplug_legacy;
+}
+
+static int vmstate_cpuhp_pre_load(void *opaque)
+{
+    ICH9LPCPMRegs *s = opaque;
+    Object *obj = OBJECT(s->gpe_cpu.device);
+    object_property_set_bool(obj, false, "cpu-hotplug-legacy", &error_abort);
+    return 0;
+}
+
+static const VMStateDescription vmstate_cpuhp_state = {
+    .name = "ich9_pm/cpuhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .needed = vmstate_test_use_cpuhp,
+    .pre_load = vmstate_cpuhp_pre_load,
+    .fields      = (VMStateField[]) {
+        VMSTATE_CPU_HOTPLUG(cpuhp_state, ICH9LPCPMRegs),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 const VMStateDescription vmstate_ich9_pm = {
     .name = "ich9_pm",
     .version_id = 1,
@@ -209,6 +236,7 @@ const VMStateDescription vmstate_ich9_pm = {
     .subsections = (const VMStateDescription*[]) {
         &vmstate_memhp_state,
         &vmstate_tco_io_state,
+        &vmstate_cpuhp_state,
         NULL
     }
 };
@@ -318,6 +346,11 @@ static void ich9_pm_set_cpu_hotplug_legacy(Object *obj, bool value,
 {
     ICH9LPCState *s = ICH9_LPC_DEVICE(obj);
 
+    assert(!value);
+    if (s->pm.cpu_hotplug_legacy && value == false) {
+        acpi_switch_to_modern_cphp(&s->pm.gpe_cpu, &s->pm.cpuhp_state,
+                                   ICH9_CPU_HOTPLUG_IO_BASE);
+    }
     s->pm.cpu_hotplug_legacy = value;
 }
 

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 858244a6612f67bbedc3b0f825b2a133b895270d..2adc246b0044174ff4595795ba062edd30ab1d0d 100644 (file)
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -276,6 +276,32 @@ static const VMStateDescription vmstate_memhp_state = {
     }
 };
 
+static bool vmstate_test_use_cpuhp(void *opaque)
+{
+    PIIX4PMState *s = opaque;
+    return !s->cpu_hotplug_legacy;
+}
+
+static int vmstate_cpuhp_pre_load(void *opaque)
+{
+    Object *obj = OBJECT(opaque);
+    object_property_set_bool(obj, false, "cpu-hotplug-legacy", &error_abort);
+    return 0;
+}
+
+static const VMStateDescription vmstate_cpuhp_state = {
+    .name = "piix4_pm/cpuhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .needed = vmstate_test_use_cpuhp,
+    .pre_load = vmstate_cpuhp_pre_load,
+    .fields      = (VMStateField[]) {
+        VMSTATE_CPU_HOTPLUG(cpuhp_state, PIIX4PMState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 /* qemu-kvm 1.2 uses version 3 but advertised as 2
  * To support incoming qemu-kvm 1.2 migration, change version_id
  * and minimum_version_id to 2 below (which breaks migration from
@@ -310,6 +336,7 @@ static const VMStateDescription vmstate_acpi = {
     },
     .subsections = (const VMStateDescription*[]) {
          &vmstate_memhp_state,
+         &vmstate_cpuhp_state,
          NULL
     }
 };
@@ -585,6 +612,11 @@ static void piix4_set_cpu_hotplug_legacy(Object *obj, bool value, Error **errp)
 {
     PIIX4PMState *s = PIIX4_PM(obj);
 
+    assert(!value);
+    if (s->cpu_hotplug_legacy && value == false) {
+        acpi_switch_to_modern_cphp(&s->gpe_cpu, &s->cpuhp_state,
+                                   PIIX4_CPU_HOTPLUG_IO_BASE);
+    }
     s->cpu_hotplug_legacy = value;
 }
 

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index e35a446a9d3117e98c222043d0639bf97324b53f..20e5b4948eceb17bed5c841f9f522ebaac435668 100644 (file)
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -33,6 +33,7 @@
 #include "hw/timer/hpet.h"
 #include "hw/acpi/acpi-defs.h"
 #include "hw/acpi/acpi.h"
+#include "hw/acpi/cpu.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/acpi/bios-linker-loader.h"
 #include "hw/loader.h"
@@ -1895,6 +1896,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
     GPtrArray *mem_ranges = g_ptr_array_new_with_free_func(crs_range_free);
     GPtrArray *io_ranges = g_ptr_array_new_with_free_func(crs_range_free);
     PCMachineState *pcms = PC_MACHINE(machine);
+    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(machine);
     uint32_t nr_mem = machine->ram_slots;
     int root_bus_limit = 0xFF;
     PCIBus *bus = NULL;
@@ -1950,7 +1952,15 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         build_q35_pci0_int(dsdt);
     }
 
-    build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
+    if (pcmc->legacy_cpu_hotplug) {
+        build_legacy_cpu_hotplug_aml(dsdt, machine, pm->cpu_hp_io_base);
+    } else {
+        CPUHotplugFeatures opts = {
+            .apci_1_compatible = true, .has_legacy_cphp = true
+        };
+        build_cpus_aml(dsdt, machine, opts, pm->cpu_hp_io_base,
+                       "\\_SB.PCI0", "\\_GPE._E02");
+    }
     build_memory_hotplug_aml(dsdt, nr_mem, pm->mem_hp_io_base,
                              pm->mem_hp_io_len);
 

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 53bc968bd071e798381493d4f2d79cc5a9c9dcfe..c7d70af2536cd4a9c5a0460b5b6e22cc5358e6ec 100644 (file)
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -445,9 +445,11 @@ DEFINE_I440FX_MACHINE(v2_7, "pc-i440fx-2.7", NULL,
 
 static void pc_i440fx_2_6_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_2_7_machine_options(m);
     m->is_default = 0;
     m->alias = NULL;
+    pcmc->legacy_cpu_hotplug = true;
     SET_MACHINE_COMPAT(m, PC_COMPAT_2_6);
 }
 

diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index e4b541f7b2ef3a98da43d6d518450a8ae87ebfd1..97a8835eea22675801e49d85f321b9abf98ddd49 100644 (file)
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -294,8 +294,10 @@ DEFINE_Q35_MACHINE(v2_7, "pc-q35-2.7", NULL,
 
 static void pc_q35_2_6_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_2_7_machine_options(m);
     m->alias = NULL;
+    pcmc->legacy_cpu_hotplug = true;
     SET_MACHINE_COMPAT(m, PC_COMPAT_2_6);
 }
 

diff --git a/include/hw/acpi/cpu.h b/include/hw/acpi/cpu.h
index 980a83c4b87ea472cd1683ed3bbb7069ccf6111e..89ce172941b81ef35151522f9c5410520124aaab 100644 (file)
--- a/include/hw/acpi/cpu.h
+++ b/include/hw/acpi/cpu.h
@@ -49,6 +49,7 @@ void cpu_hotplug_hw_init(MemoryRegion *as, Object *owner,
 
 typedef struct CPUHotplugFeatures {
     bool apci_1_compatible;
+    bool has_legacy_cphp;
 } CPUHotplugFeatures;
 
 void build_cpus_aml(Aml *table, MachineState *machine, CPUHotplugFeatures opts,

diff --git a/include/hw/acpi/cpu_hotplug.h b/include/hw/acpi/cpu_hotplug.h
index 6fef67ec1449cd43b314074f0d2e15c956386fc5..b995ef2ebd16dff57b8af3011517234ec03c99d6 100644 (file)
--- a/include/hw/acpi/cpu_hotplug.h
+++ b/include/hw/acpi/cpu_hotplug.h
@@ -16,8 +16,10 @@
 #include "hw/acpi/pc-hotplug.h"
 #include "hw/acpi/aml-build.h"
 #include "hw/hotplug.h"
+#include "hw/acpi/cpu.h"
 
 typedef struct AcpiCpuHotplug {
+    Object *device;
     MemoryRegion io;
     uint8_t sts[ACPI_GPE_PROC_LEN];
 } AcpiCpuHotplug;
@@ -28,6 +30,10 @@ void legacy_acpi_cpu_plug_cb(HotplugHandler *hotplug_dev,
 void legacy_acpi_cpu_hotplug_init(MemoryRegion *parent, Object *owner,
                                   AcpiCpuHotplug *gpe_cpu, uint16_t base);
 
+void acpi_switch_to_modern_cphp(AcpiCpuHotplug *gpe_cpu,
+                                CPUHotplugState *cpuhp_state,
+                                uint16_t io_port);
+
 void build_legacy_cpu_hotplug_aml(Aml *ctx, MachineState *machine,
                                   uint16_t io_base);
 #endif

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9e239297e8628ecb5f183e8c6fc3b333fe20081b..884224ed196017bdaf57dfd53645a5ab3fd6442d 100644 (file)
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -137,6 +137,8 @@ struct PCMachineClass {
 
     /* TSC rate migration: */
     bool save_tsc_khz;
+    /* generate legacy CPU hotplug AML */
+    bool legacy_cpu_hotplug;
 };
 
 #define TYPE_PC_MACHINE "generic-pc-machine"